The invention relates to novel compositions for the oxidation dyeing of keratin fibers, which compositions comprise at least one 3-substituted 4,5-diaminopyrazole as oxidation base, to the dyeing process using this composition, to novel 3-substituted 4,5-diaminopyrazoles and to a process for their preparation.
It is known to dye keratin fibers, and in particular human hair, with dye compositions containing oxidation dye precursors, in particular ortho- or para-phenylenediamines, ortho- or para-aminophenols and heterocyclic compounds such as diaminopyrazole derivatives, which are generally referred to as oxidation bases. The oxidation dye precursors, or oxidation bases, are colorless or weakly colored compounds which, when combined with oxidizing products, may give rise to colored compounds and dyes by a process of oxidative condensation.
It is also known that the shades obtained with these oxidation bases may be varied by combining them with couplers or coloration modifiers, the latter being chosen in particular from aromatic meta-diamines, meta-aminophenols, meta-diphenols and certain heterocyclic compounds.
The variety of molecules used as oxidation bases and couplers makes it possible to obtain a wide range of colors.
The so-called xe2x80x9cpermanentxe2x80x9d coloration obtained by means of these oxidation dyes must moreover satisfy a certain number of requirements. Thus, it must have no toxicological drawbacks and it must allow shades of the desired strength to be obtained and have good resistance to external agents (light, inclement weather, washing, permanent-waving, perspiration and friction).
The dyes must also allow white hairs to be covered and, lastly, they must be as unselective as possible, i.e., they must allow the smallest possible differences in coloration to be produced over the entire length of the same keratin fiber, which may indeed be differently sensitized (i.e. damaged) between its tip and its root.
In order to obtain red shades, para-aminophenol is usually used, alone or as a mixture with other bases, and in combination with suitable couplers, and in order to obtain blue shades, para-phenylenediamines are generally used.
European Patent Application EP-A-375,977 in particular has already proposed to use certain diaminopyrazole derivatives, namely, more precisely, 3,4- or 4,5-diaminopyrazoles, for the oxidation dyeing of keratin fibers in red shades. However, the use of the diaminopyrazoles described in EP-A-375,977 do not make it possible to obtain a wide range of colors and, furthermore, the process for the preparation of these compounds is long and expensive.
Now, the inventors have discovered, entirely unexpectedly and surprisingly, that the use of certain 3-substituted 4,5-diaminopyrazoles of formula (I) defined below for the part which is novel per se, is not only suitable for use as oxidation dye precursors but also make it possible to obtain dye compositions leading to strong colorations, in shades ranging from red to blue. Lastly, these compounds prove to be readily synthesizable.
These discoveries form the basis of the present invention.
A first subject of the invention is thus a composition for the oxidation dyeing of keratin fibers, and in particular human keratin fibers such as the hair, characterized in that it comprises, in a medium which is suitable for dyeing, at least one 3-substituted 4,5-diaminopyrazole of formula (I) below as oxidation base and/or at least one of the addition salts thereof with an acid: 
in which:
R1, R2, R3, R4 and R5 which may be identical or different, represent a hydrogen atom; a linear or branched C1-C6 alkyl radical; a C2-C4 hydroxyalkyl radical; a C2-C4 aminoalkyl radical; a phenyl radical; a phenyl radical substituted with a halogen atom or a C1-C4 alkyl, C1-C4 alkoxy, nitro, trifluoromethyl, amino or C1-C4 alkylamino radical; a benzyl radical; a benzyl radical substituted with a halogen atom or with a C1-C4 alkyl C1-C4 alkoxy, methylenedioxy or amino radical; or a radical: 
in which m and n are integers, which may be identical or different, from 1 to 3 inclusive, X represents an oxygen atom or the NH group, Y represents a hydrogen atom or a methyl radical and Z represents a methyl radical, a group OR or NRRxe2x80x2 in which R and Rxe2x80x2, which may be identical or different, denote a hydrogen atom, a methyl radical or an ethyl radical, it being understood that when R2 represents a hydrogen atom, R3 may then also represent an amino or C1-C4 alkylamino radical,
R6 represents a linear or branched C1-C6 alkyl radical; a C1-C4 hydroxyalkyl radical; a C1-C4 aminoalkyl radical; a C1-C4 dialkylamino (C1-C4) alkyl radical; a C1-C4 alkylamino (C1-C4) alkyl radical; a C1-C4 hydroxyalkylamino (C1-C4) alkyl radical; a C1-C4 alkoxymethyl radical; a phenyl radical; a phenyl radical substituted with a halogen atom or with a C1-C4 alkyl, C1-C4 alkoxy, nitro, trifluoromethyl, amino or C1-C4 alkylamino radical; a benzyl radical; a benzyl radical substituted with a halogen atom or with a C1-C4 alkyl, C1-C4 alkoxy, nitro, trifluoromethyl, amino or C1-C4 alkylamino radical; a heterocycle chosen from thiophene, furan and pyridine, or alternatively a radical xe2x80x94(CH2)pxe2x80x94Oxe2x80x94(CH2)qxe2x80x94ORxe2x80x3, in which p and q are integers, which may be identical or different, from 1 to 3 inclusive and Rxe2x80x3 represents a hydrogen atom or a methyl radical,
it being understood that, in the above formula (I):
at least one of the radicals R2, R3, R4 and R5 represents a hydrogen atom,
when R2, or respectively R4, represents a substituted or unsubstituted phenyl radical or a benzyl radical or a radical 
R3, or respectively R5, cannot then represent any of these three radicals,
when R4 and R5 simultaneously represent a hydrogen atom, R1 can then form, with R2 and R3, a hexahydropyrimidine or tetrahydroimidazole heterocycle optionally substituted with a C1-C4 alkyl or 1,2,4-tetrazole radical,
when R2, R3, R4 and R5 represent a hydrogen atom or a C1-C6 alkyl radical, R1 or R6 may then also represent a 2-, 3- or 4-pyridyl, 2- or 3-thienyl or 2- or 3-furyl heterocyclic residue optionally substituted with a methyl radical or alternatively a cyclohexyl radical.
As indicated above, the colorations obtained with the oxidation dye composition in accordance with the invention are strong and make it possible to achieve shades ranging from red to blue. One of the essential characteristics of the oxidation bases in accordance with the invention, in particular relative to those described in the abovementioned document EP-A 375,977, lies in the presence of a substituent radical R6 on the pyrazole ring.
In general, the addition salts with an acid which can be used in the context of the dye compositions of the invention (oxidation bases and couplers) are chosen in particular from the hydrochlorides, hydrobromides, sulphates, tartrates, lactates and acetates.
Among the 3-substituted 4,5-diaminopyrazoles of formula (I) which can be used as oxidation base in the compositions in accordance with the invention, mention may be made, in particular, of:
1-benzyl-4,5-diamino-3-methylpyrazole,
4,5-diamino-1-(xcex2-hydroxyethyl)-3-(4xe2x80x2-methoxyphenyl)-pyrazole,
4,5-diamino-1-(xcex2-hydroxyethyl)-3-(4xe2x80x2-methylphenyl)-pyrazole,
4,5-diamino-1-(xcex2-hydroxyethyl)-3-(3xe2x80x2-methylphenyl)-pyrazole,
4,5-diamino-3-methyl-1-isopropylpyrazole,
4,5-diamino-3-(4xe2x80x2-methoxyphenyl)-1-isopropyl-pyrazole,
4,5-diamino-1-ethyl-3-methylpyrazole,
4,5-diamino-1-ethyl-3-(4xe2x80x2-methoxyphenyl)pyrazole,
4,5-diamino-3-hydroxymethyl-1-methylpyrazole,
4,5-diamino-1-ethyl-3-hydroxymethylpyrazole,
4,5-diamino-3-hydroxymethyl-1-isopropylpyrazole,
4,5-diamino-3-hydroxymethyl-1-tert-butylpyrazole,
4,5-diamino-3-hydroxymethyl-1-phenylpyrazole,
4,5-diamino-3-hydroxymethyl-1-(2xe2x80x2-methoxyphenyl)-pyrazole,
4,5-diamino-3-hydroxymethyl-1-(3xe2x80x2-methoxyphenyl)-pyrazole,
4,5-diamino-3-hydroxymethyl-1-(4xe2x80x2-methoxyphenyl)-pyrazole,
1-benzyl-4,5-diamino-3-hydroxymethyl pyrazole,
4,5-diamino-3-methyl-1-(2xe2x80x2-methoxyphenyl)pyrazole,
4,5-diamino-3-methyl-1-(3xe2x80x2-methoxyphenyl)pyrazole,
4,5-diamino-3-methyl-1-(4xe2x80x2-methoxyphenyl)pyrazole,
3-aminomethyl-4,5-diamino-1-methylpyrazole,
3-aminomethyl-4,5-diamino-1-ethylpyrazole,
3-aminomethyl-4,5-diamino-1-isopropylpyrazole,
3-aminomethyl-4,5-diamino-1-tert-butylpyrazole,
4,5-diamino-3-dimethylaminomethyl-1-methylpyrazole,
4,5-diamino-3-dimethylaminomethyl-1-ethylpyrazole,
4,5-diamino-3-dimethylaminomethyl-1-isopropyl-pyrazole,
4,5-diamino-3-dimethylaminomethyl-1-tert-butyl-pyrazole,
4,5-diamino-3-ethylaminomethyl-1-methylpyrazole,
4,5-diamino-3-ethylaminomethyl-1-ethylpyrazole,
4,5-diamino-3-ethylaminomethyl-1-isopropylpyrazole,
4,5-diamino-3-ethylaminomethyl-1-tert-butylpyrazole.
4,5-diamino-3-methylaminomethyl-1-methylpyrazole,
4,5-diamino-3-methylaminomethyl-1-isopropylpyrazole,
4,5-diamino-1-ethyl-3-methylaminomethylpyrazole,
1-tert-butyl-4,5-diamino-3-methylaminomethyl-pyrazole,
4,5-diamino-3-[(xcex2-hydroxyethyl)aminomethyl]-1-methyl-pyrazole,
4,5-diamino-3-[(xcex2-hydroxyethyl)aminomethyl]-1-isopropylpyrazole,
4,5-diamino-1-ethyl-3-[(xcex2-hydroxyethyl)aminomethyl]-pyrazole,
1-tert-butyl-4,5-diamino-3-[(xcex2-hydroxyethyl)amino-methyl]pyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1,3-dimethylpyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-isopropyl-3-methyl-pyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-ethyl-3-methyl-pyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-tert-butyl-3-methylpyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-phenyl-3-methyl-pyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-(2-methoxyphenyl)-3-methylpyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-(3-methoxyphenyl)-3-methylpyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-(4-methoxyphenyl)-3-methylpyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-benzyl-3-methyl-pyrazole,
4-amino-1-ethyl-3-methyl-5-methylaminopyrazole,
4-amino-1-tert-butyl-3-methyl-5-methylaminopyrazole,
4,5-diamino-1,3-dimethylpyrazole,
4,5-diamino-3-tert-butyl-1-methylpyrazole,
4,5-diamino-1-tert-butyl-3-methylpyrazole,
4,5-diamino-1-methyl-3-phenylpyrazole,
4,5-diamino-1-(xcex2-hydroxyethyl)-3-methylpyrazole,
4,5-diamino-1-(xcex2-hydroxyethyl)-3-phenylpyrazole,
4,5-diamino-1-methyl-3-(2xe2x80x2-chlorophenyl)pyrazole,
4,5-diamino-1-methyl-3-(4xe2x80x2-chlorophenyl)pyrazole,
4,5-diamino-1-methyl-3-(3xe2x80x2-trifluoromethylphenyl)-pyrazole,
4,5-diamino-1,3-diphenylpyrazole,
4,5-diamino-3-methyl-1-phenylpyrazole,
4-amino-1,3-dimethyl-5-phenylaminopyrazole,
4-amino-1-ethyl-3-methyl-5-phenylaminopyrazole,
4-amino-1,3-dimethyl-5-methylaminopyrazole,
4-amino-3-methyl-1-isopropyl-5-methylaminopyrazole,
4-amino-3-isobutoxymethyl-1-methyl-5-methylamino-pyrazole,
4-amino-3-methoxyethoxymethyl-1-methyl-5-methylamino-pyrazole,
4-amino-3-hydroxymethyl-1-methyl-5-methylamino-pyrazole,
4-amino-1,3-diphenyl-5-phenylaminopyrazole,
4-amino-3-methyl-5-methylamino-1-phenylpyrazole,
4-amino-1,3-dimethyl-5-hydrazinopyrazole,
5-amino-3-methyl-4-methylamino-1-phenylpyrazole,
5-amino-1-methyl-4-(N-methyl-N-phenyl)amino-3-(4xe2x80x2-chlorophenyl)pyrazole,
5-amino-3-ethyl-1-methyl-4-(N-methyl-N-phenyl)amino-pyrazole,
5-amino-1-methyl-4-(N-methyl-N-phenyl)amino-3-phenyl-pyrazole,
5-amino-3-ethyl-4-(N-methyl-N-phenyl)aminopyrazole,
5-amino-4-(N-methyl-N-phenyl)amino-3-phenylpyrazole,
5-amino-4-(N-methyl-N-phenyl)amino-3-(4xe2x80x2-methylphenyl)pyrazole,
5-amino-3-(4xe2x80x2-chlorophenyl)-4-(N-methyl-N-phenyl)aminopyrazole,
5-amino-3-(4xe2x80x2-methoxyphenyl)-4-(N-methyl-N-phenyl)aminopyrazole,
4-amino-5-methylamino-3-phenylpyrazole,
4-amino-5-ethylamino-3-phenylpyrazole,
4-amino-5-ethylamino-3-(4xe2x80x2-methylphenyl)pyrazole,
4-amino-3-phenyl-5-propylaminopyrazole,
4-amino-5-butylamino-3-phenylpyrazole,
4-amino-3-phenyl-5-phenylaminopyrazole,
4-amino-5-butylamino-3-phenylpyrazole,
4-amino-5-(4xe2x80x2-chlorophenyl)amino-3-phenylpyrazole,
4-amino-3-(4xe2x80x2-chlorophenyl)-5-phenylaminopyrazole,
4-amino-3-(4xe2x80x2-methoxyphenyl)-5-phenylaminopyrazole,
1-(4xe2x80x2-chlorobenzyl)-4,5-diamino-3-methylpyrazole,
4,5-diamino-3-hydroxymethyl-1-isopropylpyrazole,
4-amino-1-ethyl-3-methyl-5-methylaminopyrazole,
4-amino-5-(2xe2x80x2-aminoethyl)amino-1,3-dimethyl-pyrazole,
and the addition salts thereof with an acid.
Among these 3-substituted 4,5-diaminopyrazoles, the following are more particularly preferred:
4,5-diamino-1,3-dimethylpyrazole,
4,5-diamino-3-methyl-1-phenylpyrazole,
4,5-diamino-1-methyl-3-phenylpyrazole,
4-amino-1,3-dimethyl-5-hydrazinopyrazole,
1-benzyl-4,5-diamino-3-methylpyrazole,
4,5-diamino-3-tert-butyl-1-methylpyrazole,
4,5-diamino-1-tert-butyl-3-methylpyrazole,
4,5-diamino-1-(xcex2-hydroxyethyl)-3-methylpyrazole,
4,5-diamino-1-ethyl-3-methylpyrazole,
4,5-diamino-1-ethyl-3-(4xe2x80x2-methoxyphenyl)pyrazole,
4,5-diamino-1-ethyl-3-hydroxymethylpyrazole,
4,5-diamino-3-hydroxymethyl-1-methylpyrazole,
4,5-diamino-3-hydroxymethyl-1-isopropylpyrazole,
4,5-diamino-3-methyl-1-isopropylpyrazole,
4-amino-5-(2xe2x80x2-aminoethyl)amino-1,3-dimethylpyrazole,
and the addition salts thereof with an acid.
The 3-substituted 4,5-diaminopyrazole(s) of formula (I) above preferably represent from 0.0005 to 12% by weight approximately relative to the total weight of the dye composition, and even more preferably from 0.005 to 6% by weight approximately relative to this weight.
The appropriate medium for the dyeing (or the support) generally comprises water or a mixture of water and at least one organic solvent to solubilize the compounds which would not be sufficiently soluble in water. Organic solvents which may be mentioned, for example, are C1-C4 lower alkanols such as ethanol and isopropanol; glycerol; glycols and glycol ethers such as 2-butoxyethanol, propylene glycol, propylene glycol monomethyl ether, diethylene glycol monomethyl ether and monoethyl ether, as well as aromatic alcohols such as benzyl alcohol or phenoxyethanol, similar products and mixtures thereof.
The solvents may be present in proportions preferably of approximately from 1 to 40% by weight relative to the total weight of the dye composition, and even more preferably of approximately from 5 to 30% by weight.
The pH of the dye composition in accordance with the invention is generally from 3 to 12 and preferably is approximately from 5 to 11. It may be adjusted to the desired value using acidifying or basifying agents usually used in the dyeing of keratin fibers.
Among the acidifying agents which may be mentioned, by way of example, are inorganic or organic acids such as hydrochloric acid, orthophosphoric acid, sulfuric acid, carboxylic acids such as acetic acid, tartaric acid, citric acid and lactic acid, and sulphonic acids.
Among the basifying agents which may be mentioned, by way of example, are aqueous ammonia, alkaline carbonates, alkanolamines such as mono-, di- and triethanolamines and derivatives thereof, sodium hydroxide, potassium hydroxide and the compounds of following formula (II): 
in which W is a propylene residue optionally substituted with a hydroxyl group or a C1-C4 alkyl radical; R8, R9, R10 and R11, which may be identical or different, represent a hydrogen atom or a C1-C4 alkyl or C1-C4 hydroxyalkyl radical.
In addition to the dyes defined above, the dye composition in accordance with the invention may also contain at least one additional oxidation base which may be chosen from the oxidation bases conventionally used in oxidation dyeing and from which mention may be made, in particular, of para-phenylenediamines, bis(phenylalkylenediamines), para-aminophenols, ortho-aminophenols and heterocyclic bases other than the 3-substituted 4,5-diaminopyrazoles used in accordance with the invention.
Among the para-phenylenediamines which may be mentioned more particularly as examples are para-phenylenediamine, para-toluylenediamine, 2,6-dimethyl-para-phenylenediamine, 2-xcex2-hydroxyethyl-para-phenylenediamine, 2-n-propyl-para-phenylenediamine, 2-isopropyl-para-phenylenediamine, N-(xcex2-hydroxypropyl)-para-phenylenediamine, N,N-bis(xcex2-hydroxyethyl)-para-phenylenediamine, 4-amino-N-(xcex2-methoxyethyl)aniline, the para-phenylenediamines described in French patent application FR 2,630,438, the disclosure of which is hereby incorporated by reference, and the addition salts thereof with an acid.
Among the bis(phenylalkylenediamines) which may be mentioned more particularly as examples are N,Nxe2x80x2-bis(xcex2-hydroxyethyl)-N,Nxe2x80x2-bis(4xe2x80x2-aminophenyl)-1,3-diaminopropanol, N,Nxe2x80x2-bis(xcex2-hydroxyethyl)-N,Nxe2x80x2-bis(4xe2x80x2-aminophenyl)ethylenediamine, N,Nxe2x80x2-bis(4-aminophenyl)-tetramethylenediamine, N,Nxe2x80x2-bis(xcex2-hydroxyethyl)-N,Nxe2x80x2-bis(4-aminophenyl)tetramethylenediamine, N,Nxe2x80x2-bis(4-methylaminophenyl)tetramethylenediamine, N,Nxe2x80x2-bis(ethyl)-N,Nxe2x80x2-bis(4xe2x80x2-amino-3xe2x80x2-methylphenyl)ethylene-diamine, and the addition salts thereof with an acid.
Among the para-aminophenols which may be mentioned more particularly as examples are para-aminophenol, 4-amino-3-methylphenol, 4-amino-3-fluorophenol, 4-amino-3-hydroxymethylphenol, 4-amino-2-methylphenol, 4-amino-2-hydroxymethylphenol, 4-amino-2-methoxymethylphenol, 4-amino-2-aminomethylphenol, 4-amino-2-(xcex2-hydroxyethylaminomethyl)phenol, and the addition salts thereof with an acid.
Among the ortho-aminophenols which may be mentioned more particularly as examples are 2-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol, 5-acetamido-2-aminophenol, and the addition salts thereof with an acid.
Among the heterocyclic bases which may be mentioned more particularly as examples are pyridine derivatives, pyrimidine derivatives, pyrazole derivatives other than the 3-substituted 4,5-diaminopyrazoles used in accordance with the invention, and the addition salts thereof with an acid.
When they are used, these additional oxidation bases preferably represent from 0.0005 to 12% by weight approximately relative to the total weight of the dye composition, and even more preferably from 0.005 to 6% by weight approximately relative to this weight.
The oxidation dye compositions in accordance with the invention may also contain at least one coupler and/or at least one direct dye, in particular to modify the shades or enrich them with glints.
The couplers which can be used in the oxidation dye compositions in accordance with the invention may be chosen from the couplers used conventionally in oxidation dyeing and among which mention may be made in particular of meta-phenylenediamines, meta-aminophenols, meta-diphenols and heterocyclic couplers such as, for example, indole derivatives, indoline derivatives, pyridine derivatives and pyrazolones, and the addition salts thereof with an acid.
These couplers are chosen more particularly from 2-methyl-5-aminophenol, 5-N-(xcex2-hydroxyethyl)amino-2-methylphenol, 3-aminophenol, 1,3-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene, 4-chloro-1,3-dihydroxybenzene, 2,4-diamino-1-(xcex2-hydroxyethyloxy)-benzene, 2-amino-4-(xcex2-hydroxyethylamino)-1-methoxybenzene, 1,3-diaminobenzene, 1,3-bis(2,4-diaminophenoxy)propane, sesamol xcex1-naphthol, 6-hydroxyindole, 4-hydroxyindole, 4-hydroxy-N-methylindole, 6-hydroxyindoline, 2,6-dihydroxy-4-methylpyridine, 1-H-3-methyl-5-pyrazolone, 1-phenyl-3-methyl-5-pyrazolone, and the addition salts thereof with an acid.
When they are present, these couplers preferably represent from 0.0001 to 10% by weight approximately relative to the total weight of the dye composition, and even more preferably from 0.005 to 5% by weight approximately relative to this weight.
The dye composition according to the invention may also contain various adjuvants used conventionally in compositions for dyeing the hair, such as anionic, cationic, nonionic, amphoteric or zwitterionic surfactants or mixtures thereof, anionic, cationic, nonionic, amphoteric or zwitterionic polymers or mixtures thereof, inorganic or organic thickeners, antioxidants, penetration agents, sequestering agents, fragrances, buffers, dispersing agents, conditioners such as, for example, silicones, film-forming agents, preserving agents and opacifying agents.
Obviously, a person skilled in the art will take care to select this or these optional complementary compounds such that the advantageous properties intrinsically attached to the oxidation dye composition in accordance with the invention are not, or are substantially not, damaged by the additions envisaged.
The dye composition according to the invention may be in various forms, such as in the form of liquids, creams or gels or any other form which is suitable for dyeing keratin fibers, and in particular human hair.
The subject of the invention is also a process for dyeing keratin fibers, and in particular human keratin fibers such as the hair, which uses the dye composition as defined above.
According to this process, at least one dye composition as defined above is applied to the fibers, for a period which is sufficient to develop the desired coloration, either in air or with the aid of an oxidizing agent.
According to a first embodiment of the process of the invention, the fibers may be dyed without addition of an oxidizing agent, merely by contact with atmospheric oxygen. In this case, the dye composition may then optionally contain oxidation catalysts, so as to accelerate the oxidation process.
Oxidation catalysts which may be mentioned more particularly are metal salts such as manganese, cobalt, copper, iron, silver and zinc salts.
Such compounds are, for example, manganese diacetate tetrahydrate, manganese dichloride and its hydrates, manganese dihydrogen carbonate, manganese acetylacetonate, manganese triacetate and its hydrates, manganese trichloride, zinc dichloride, zinc diacetate dihydrate, zinc carbonate, zinc dinitrate, zinc sulphate, iron dichloride, iron sulphate, iron diacetate, cobalt diacetate tetrahydrate, cobalt carbonate, cobalt dichloride, cobalt dinitrate, cobalt sulphate heptahydrate, cupric chloride and ammoniacal silver nitrate.
The manganese salts are particularly preferred.
When they are used, these metal salts are generally used in proportions ranging from 0.001 to 4% by weight of metal equivalent relative to the total weight of the dye composition, and preferably from 0.005 to 2% by weight of metal equivalent relative to the total weight of the dye composition.
According to a second embodiment of the process of the invention, at least one dye composition as defined above is applied to the fibers, the colour being developed at acidic, neutral or alkaline pH using an oxidizing agent which is added, only at the time of use, to the dye composition or which is present in an oxidizing composition that is applied simultaneously or sequentially in a separate manner.
According to this second embodiment of the dyeing process of the invention, the dye composition described above is preferably mixed, at the time of use, with an oxidizing composition containing, in a medium which is suitable for dyeing, at least one oxidizing agent present in an amount which is sufficient to develop a coloration. The mixture obtained is then applied to the keratin fibers and is generally left in place for 3 to 50 minutes approximately, preferably for 5 to 30 minutes approximately, after which the fibers are rinsed, washed with shampoo, rinsed again and dried.
The oxidizing agent present in the oxidizing composition as defined above may be chosen from the oxidizing agents conventionally used for the oxidation dyeing of keratin fibers, and among which mention may be made of hydrogen peroxide, urea peroxide, alkali metal bromates and persalts such as perborates and persulphates. Hydrogen peroxide is particularly preferred.
The pH of the oxidizing composition containing the oxidizing agent as defined above is such that, after mixing with the dye composition, the pH of the resulting composition applied to the keratin fibers preferably ranges from 3 to 12 approximately, and even more preferably from 5 to 11. It is adjusted to the desired value using acidifying or basifying agents usually used in the dyeing of keratin fibers and as defined above.
The oxidizing composition as defined above may also contain various adjuvants conventionally used in compositions for dyeing the hair and as defined above.
The composition which is finally applied to the keratin fibers may be in various forms, such as in the form of liquids, creams or gels or in any other form which is suitable for dyeing keratin fibers, and in particular human hair.
Another subject of the invention is a multi-compartment device or dyeing kit or any other multi-compartment packaging system, a first compartment of which contains the dye composition as defined above and a second compartment of which contains the oxidizing composition as defined above. These devices may be equipped with a means which makes it possible to deliver the desired mixture onto the hair, such as the devices described in French patent FR-2,586,913 in the name of the present assignee, the disclosure of which is hereby incorporated by reference.
Certain compounds of formula (I), used as oxidation base in the context of the present invention, are novel and, in this respect, constitute another subject of the invention.
These novel 3-substituted 4,5-diamino-pyrazoles and the addition salts thereof with an acid correspond to the following formula (Ixe2x80x2): 
in which Rxe2x80x21, Rxe2x80x22, Rxe2x80x23, Rxe2x80x24, Rxe2x80x25 and Rxe2x80x26 have the same meanings as those indicated above for the radicals R1, R2, R3, R4, R5, and R6 in the formula (I), with, however, the following provisos:
(i) when Rxe2x80x21 represents a methyl radical, and when Rxe2x80x22, Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, and when Rxe2x80x23 represents a hydrogen atom or a methyl radical, Rxe2x80x26 is then other than a hydroxymethyl, isobutyloxymethyl, methoxyethyloxymethyl, cyclohexyl, thiophene, pyridine or phenyl radical or phenyl radical substituted with a methyl radical or with a trifluoromethyl radical or with a chlorine atom;
(ii) when Rxe2x80x21 represents an unsubstituted phenyl radical and when Rxe2x80x22, Rxe2x80x23, Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, Rxe2x80x26 is then other than an unsubstituted phenyl radical;
(iii) when Rxe2x80x21 represents an unsubstituted phenyl radical, and when Rxe2x80x26 represents a methyl radical, and when Rxe2x80x22, Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, Rxe2x80x23 is then other than a hydrogen atom, a methyl radical or an unsubstituted phenyl radical;
(iv) when Rxe2x80x21 represents an unsubstituted phenyl radical, and when Rxe2x80x26 represents a methyl radical, and when Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, and when Rxe2x80x22 represents a methyl or ethyl radical, Rxe2x80x23 is then other than an unsubstituted phenyl radical;
(v) when Rxe2x80x21 represents an unsubstituted phenyl radical, and when Rxe2x80x26 represents a methyl radical, and Rxe2x80x22, Rxe2x80x23 and Rxe2x80x25 simultaneously represent a hydrogen atom, Rxe2x80x24 is then other than a methyl radical;
(vi) when Rxe2x80x22, Rxe2x80x23, Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, and when Rxe2x80x26 represents a methyl radical, Rxe2x80x21 is then other than a phenyl radical substituted with a chlorine atom or with a trifluoroethyl, nitro or pyridyl radical;
(vii) when Rxe2x80x21 represents a hydrogen atom, and when Rxe2x80x26 represents a phenyl radical or a phenyl radical substituted with a chlorine atom or with a methyl or methoxy radical, and when Rxe2x80x22, Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, Rxe2x80x23 is then other than a hydrogen atom or a C1-C4 alkyl or unsubstituted phenyl radical;
(viii) when Rxe2x80x21, Rxe2x80x22, Rxe2x80x23, Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, Rxe2x80x26 is then other than a methyl radical;
(ix) when Rxe2x80x21 represents a xcex2-hydroxyethyl radical, and when Rxe2x80x22, Rxe2x80x23, Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, Rxe2x80x26 is then other than a methyl or unsubstituted phenyl radical;
(x) when Rxe2x80x24 represents a methyl radical, and when Rxe2x80x25 represents an unsubstituted phenyl radical, and when Rxe2x80x22 and Rxe2x80x23 simultaneously represent a hydrogen atom, and when Rxe2x80x21 represents a hydrogen atom or a methyl radical, Rxe2x80x26 is then other than an unsubstituted phenyl radical or a phenyl radical substituted with a methyl, ethyl or methoxy-radical or with a chlorine atom;
(xi) when Rxe2x80x21 represents a tert-butyl radical, and when Rxe2x80x22, Rxe2x80x23, Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, Rxe2x80x26 is then other than a methyl radical;
(xii) when Rxe2x80x21 represents a pyridyl radical, and when Rxe2x80x22, Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, and when Rxe2x80x23 represents a hydrogen atom or a methyl radical, Rxe2x80x26 is then other than a methyl or unsubstituted phenyl radical;
(xiii) when Rxe2x80x21 represents a methyl, ethyl or 4-aminophenyl radical, and when Rxe2x80x22, Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, and when Rxe2x80x23 represents a hydrogen atom or an unsubstituted phenyl radical, Rxe2x80x26 is then other than a methyl radical;
(xiv) when Rxe2x80x21 represents an isopropyl radical, and when Rxe2x80x22, Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, at least one of the radicals Rxe2x80x23 and Rxe2x80x26 is then other than a methyl radical;
(xv) when Rxe2x80x21 represents a hydrogen atom or an unsubstituted phenyl radical, and when Rxe2x80x22, Rxe2x80x24 and Rxe2x80x25 simultaneously represent a hydrogen atom, and when Rxe2x80x23 represents a benzyl radical or a phenyl radical substituted with a methyl radical or with a chlorine atom, Rxe2x80x26 is then other than a methyl or unsubstituted phenyl radical.
Among the novel compounds of formula (Ixe2x80x2) which may be mentioned in particular are:
1-benzyl-4,5-diamino-3-methylpyrazole,
4,5-diamino-1-(xcex2-hydroxyethyl)-3-(4xe2x80x2-methoxyphenyl)-pyrazole,
4,5-diamino-1-(xcex2-hydroxyethyl)-3-(4xe2x80x2-methylphenyl)-pyrazole,
4,5-diamino-1-(xcex2-hydroxyethyl)-3-(3xe2x80x2-methylphenyl)-pyrazole,
4,5-diamino-3-methyl-1-isopropylpyrazole,
4,5-diamino-3-(4xe2x80x2-methoxyphenyl)-1-isopropyl-pyrazole,
4,5-diamino-1-ethyl-3-methylpyrazole,
4,5-diamino-1-ethyl-3-(4xe2x80x2-methoxyphenyl)pyrazole,
4,5-diamino-3-hydroxymethyl-1-methylpyrazole,
4,5-diamino-1-ethyl-3-hydroxymethylpyrazole,
4,5-diamino-3-hydroxymethyl-1-isopropylpyrazole,
4,5-diamino-3-hydroxymethyl-1-tert-butylpyrazole,
4,5-diamino-3-hydroxymethyl-1-phenylpyrazole,
4,5-diamino-3-hydroxymethyl-1-(2xe2x80x2-methoxyphenyl)-pyrazole,
4,5-diamino-3-hydroxymethyl-1-(3xe2x80x2-methoxyphenyl)-pyrazole,
4,5-diamino-3-hydroxymethyl-1-(4xe2x80x2-methoxyphenyl)-pyrazole,
1-benzyl-4,5-diamino-3-hydroxymethylpyrazole,
4,5-diamino-3-methyl-1-(2xe2x80x2-methoxyphenyl)pyrazole,
4,5-diamino-3-methyl-1-(3xe2x80x2-methoxyphenyl)pyrazole,
4,5-diamino-3-methyl-1-(4xe2x80x2-methoxyphenyl)pyrazole,
3-aminomethyl-4,5-diamino-1-methylpyrazole,
3-aminomethyl-4,5-diamino-1-ethylpyrazole,
3-aminomethyl-4,5-diamino-1-isopropylpyrazole,
3-aminomethyl-4,5-diamino-1-tert-butylpyrazole,
4,5-diamino-3-dimethylaminomethyl-1-methylpyrazole,
4,5-diamino-3-dimethylaminomethyl-1-ethylpyrazole,
4,5-diamino-3-dimethylaminomethyl-1-isopropyl-pyrazole,
4,5-diamino-3-dimethylaminomethyl-1-tert-butyl-pyrazole,
4,5-diamino-3-ethylaminomethyl-1-methylpyrazole,
4,5-diamino-3-ethylaminomethyl-1-ethylpyrazole,
4,5-diamino-3-ethylaminomethyl-1-isopropylpyrazole,
4,5-diamino-3-ethylaminomethyl-1-tert-butylpyrazole,
4,5-diamino-3-methylaminomethyl-1-methylpyrazole,
4,5-diamino-3-methylaminomethyl-1-isopropylpyrazole,
4,5-diamino-1-ethyl-3-methylaminomethylpyrazole,
1-tert-butyl-4,5-diamino-3-methylaminomethyl-pyrazole,
4,5-diamino-3-[(xcex2-hydroxyethyl)aminomethyl]-1-methyl-pyrazole,
4,5-diamino-3-[(xcex2-hydroxyethyl)aminomethyl]-1-isopropylpyrazole,
4,5-diamino-1-ethyl-3-[(xcex2-hydroxyethyl)aminomethyl]-pyrazole,
1-tert-butyl-4,5-diamino-3-[(xcex2-hydroxyethyl)amino-methyl]pyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1,3-dimethylpyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-isopropyl-3-methyl-pyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-ethyl-3-methyl-pyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-tert-butyl-3-methylpyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-phenyl-3-methyl-pyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-(2xe2x80x2-methoxyphenyl)-3-methylpyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-(3xe2x80x2-methoxyphenyl)-3-methylpyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-(4xe2x80x2-methoxyphenyl)-3-methylpyrazole,
4-amino-5-(xcex2-hydroxyethyl)amino-1-benzyl-3-methyl-pyrazole,
4-amino-1-ethyl-3-methyl-5-methylaminopyrazole,
4-amino-1-tert-butyl-3-methyl-5-methylaminopyrazole,
1-(4xe2x80x2-chlorobenzyl)-4,5-diamino-3-methylpyrazole,
4,5-diamino-3-hydroxymethyl-1-isopropylpyrazole,
4-amino-1-ethyl-3-methyl-5-methylaminopyrazole,
4-amino-5-(2xe2x80x2-aminoethyl)amino-1,3-dimethylpyrazole,
and the addition salts thereof with an acid.
Among the novel compounds of formula (Ixe2x80x2) which are more particularly preferred are:
1-benzyl-4,5-diamino-3-methylpyrazole,
4,5-diamino-1-ethyl-3-methylpyrazole,
4,5-diamino-1-ethyl-3-(4xe2x80x2-methoxyphenyl)pyrazole,
4,5-diamino-1-ethyl-3-hydroxymethylpyrazole,
4,5-diamino-3-hydroxymethyl-1-methylpyrazole,
4,5-diamino-3-hydroxymethyl-1-isopropylpyrazole,
4,5-diamino-3-methyl-1-isopropylpyrazole,
4-amino-5-(2xe2x80x2-aminoethyl)amino-1,3-dimethyl-pyrazole,
and the addition salts thereof with an acid.
The subject of the invention is also processes for the preparation of the novel compounds of formula (Ixe2x80x2).
When Rxe2x80x26 represents a methyl radical, and when Rxe2x80x21 is other than a hydrogen atom, (compounds of formula (Ixe2x80x2A) below), process A corresponding to the following synthetic scheme: 
is preferably used, this reaction scheme comprising reacting, in a first step, a 3-aminocrotononitrile (1) with a monosubstituted hydrazine (2), at a temperature generally above 90xc2x0 C., and preferably from 95 to 150xc2x0 C., in an alcoholic solvent, followed, in a second step, in nitrosing the 5-aminopyrazole (3) in the 4-position, by reaction with an inorganic or organic nitrite, in order to give the 5-amino 4-nitrosopyrazole (4) which leads, in a third step, by catalytic hydrogenation to the 4,5-diaminopyrazoles of formula (Ixe2x80x2A).
In order to have good control over the temperature during the first step, it is generally preferred to work at the reflux temperature of the solvent used. Among the alcohols used as reaction solvent which may be mentioned more particularly are n-propanol, 1-butanol, 2-butanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-1-propanol, n-pentanol, 2-pentanol, 3-methyl-3-pentanol, 4-methyl-2-pentanol or 2-ethyl-1-butanol.
Among the inorganic nitrites which may be used, for example, are sodium nitrite or potassium nitrite, in aqueous acetic acid medium, at a temperature preferably from 0 to 5xc2x0 C.
Among the organic nitrites which may be used, for example, is isoamyl nitrite, the reaction being carried out at room temperature, in a lower alcohol in the presence of an acid such as hydrochloric acid or acetic acid.
The catalytic hydrogenation of the compounds (4) is preferably carried out in a lower alcohol, in the presence of a catalyst such as palladium-on-charcoal, at a temperature generally of from 20 to 100xc2x0 C.
When Rxe2x80x26 is other than a methyl radical, and when Rxe2x80x21 is other than a hydrogen atom (compounds of formula (Ixe2x80x2B) below), process B corresponding to the following synthetic scheme: 
is preferably used, this synthetic scheme comprising reacting, in a first step, a xcex2-keto acetonitrile (5) with a monosubstituted hydrazine (2), at a temperature generally of from 20 to 150xc2x0 C., in an alcoholic solvent, in order to obtain the 5-aminopyrazole (6), which is then nitrosated in the 4-position, in a second step, to give a 4-nitro-5-aminopyrazole (7), which is itself then hydrogenated, in a third step, to lead to the 4,5-diaminopyrazoles of formula (Ixe2x80x2B).
The solvents used according to this process B are the same as those mentioned for the process A described above.
The nitrosation and hydrogenation reactions are performed according to the conditions described for process A described above.
When Rxe2x80x26 represents a radical which is of high steric bulk (compounds of formula (Ixe2x80x2C) below), process C corresponding to the following synthetic scheme: 
is preferably used, this synthetic scheme comprising reacting, in a first step, a xcex2-keto acetonitrile (5) with a monosubstituted hydrazine (2) in order to obtain a 5-amino-pyrazole (6) according to the operating conditions mentioned for process B described above. The 5-amino-pyrazole (6) is then acetylated in the 5-position, in a second step, to lead to a 5-acetylaminopyrazole (8), which is itself then nitrated in the 4-position and deacetylated in the 5-position, in a third step, to give a 5-amino-4-nitropyrazole (9), preferably by fuming nitric acid in concentrated sulphuric medium, at a temperature preferably of from 0 to 5xc2x0 C. The 5-amino-4-nitropyrazole (9) is then hydrogenated, in a fourth step, according to the operating conditions mentioned in process A above, to lead to the 4,5-diaminopyrazoles of formula (Ixe2x80x2C).
When one of the radicals Rxe2x80x22 or Rxe2x80x23 is other than a hydrogen atom (compounds of formula (Ixe2x80x2D) below), process D corresponding to the following synthetic scheme: 
is preferably used, this synthetic scheme comprising reacting, in a first step, a xcex2-keto ester (10) with a hydrazine (2) in order to obtain a 5-hydroxypyrazole (11), which is in equilibrium with its 5-pyrazolone tautomeric form, as described, for example, in Org. Synth., Edward C. Taylor (1976), 55, 73-7. The 5-hydroxypyrazole (11) is then nitrated in the 4-position, in a second step, and then chlorinated in the 5-position, in a third step, according to the method as described, for example, in U.S. Pat. No. 4,025,530. The 5-chloro-4-nitropyrazole (13) then leads, in a fourth step, in the presence of a primary amine H2Nxe2x80x94Rxe2x80x23, to a 5-amino-4-nitropyrazole (14) and then, in a fifth step, by catalytic hydrogenation according to the method described above for process A, to the 4,5-diaminopyrazoles of formula (Ixe2x80x2D).
The examples which follow are intended to illustrate the invention without, however, limiting the scope thereof.